1. Field of the Invention
The present invention relates to a communicating apparatus for performing communication over an IP (Internet Protocol) network by using an SIP (Session Initiation Protocol), a controlling method therefor, and a program.
2. Description of the Related Art
In recent years, infrastructure of a next-generation network such as the NGN (Next Generation Network) is being established, and accordingly ways of communication are being shifted from analog networks to IP networks. In such circumstances, IP-FAX communication that is carried out via an intranet under the same scheme as that of the FAX communication has started and it is anticipated that the IP-FAX communication is going to be in increasing demand.
In addition, for SIP (Session Initiation Protocol) communication, there is a system developed for improving the communication between two terminals in the case where firewall software is respectively installed in routers of the two terminals (for example, see Japanese Patent No. 4080169).
Meanwhile, in the network field, measures to achieve improved security against vulnerabilities of communication systems are urgently necessary, and the same is also true of the IP-FAX. For example, as part of the security measures, in order to avoid IP-FAX incoming from a device having some problem, there is a technique for blocking the communication from a particular device by blocking incoming from a telephone number and incoming from a domain other than a specified domain and by filtering a specified IP address.
However, in the security measures such as the IP filtering used by the conventional IP-FAX, each time an IP address or the like of the particular device is changed, the settings need to be reset. In addition, it is difficult to block the communication from the particular device perfectly, because resources for setting the filters are limited. Consequently, a device may be subject to a DoS (Denial of Service) attack, a DDoS (Distributed Denial of Service) attack, and the like.